The equatorial region of Jupiter, characterized by a wide eastward
jet, needs to be treated differently. Gravity analysis reveals that
Jupiter's interior (deeper than \(\sim 3000\,\,{\rm km}\) ) is rotating
as a rigid body [1]}. Extending the zonal wind along
the direction of the spin axis thus separates the equatorial region
(\(17^{\circ }\,{\rm S}\)  to \(17^{\circ }\,{\rm N}\) ) from the truncated
cells at midlatitudes (see SI). The superrotating wind at low latitudes
requires a source of momentum [2]}. Theories for such
sources include meridional [3]}, [4]} and vertical
[5]}, [6]}, [7]}, [8]}, [9]}, [10]}, propagation of waves. For the vertical case, several
studies have shown that an equatorial superrotation in giant planets
can be driven by eddy momentum fluxes perpendicular to the axis of
rotation [8]}, [9]}, [13]}. These fluxes
transfer momentum outwards and lead to a mean upwelling at the equatorial
region (see SI). Such an upwelling should lead to a maximum concentration
anomaly of any stably stratified matter (Fig. REF e).
In the equatorial region, the minimum in \(M_{{\rm a}}\)  around \(\sim 6\) 
bar nearly vanishes (Fig. S8), suggesting that the positive ammonia
anomalies at the equatorial region (Fig. S2a) are due to the upwelling
from deep. To examine this, at the equator, the correlation is calculated
between the zonal velocity (\(\bar{u}\) ) and the ammonia concentration
itself (\(-T_{{\rm b}}\)  for the MWR or \({\rm NH_{3}}\)  for the JIRAM
measurements). Using a regional correlation analysis (see SI), it
is apparent that the correlations are largely positive at all depths
(Fig. REF b,e), implying that an equatorial upwelling
is dominant from the cloud deck and down to at least 240 bar.
Very close to the equator, the correlation is negative due to the
local minimum in the zonal velocity (Fig. REF b).
